The present disclosure relates to a control system for a platform screen door system and a method of operating the closing of the doors of the platform screen door system.
The conventional railway station consisting of a raised platform adjacent to the track is essentially the same design as has been used since the beginning of the railway industry in the nineteenth century and is an effective solution to the problem of maximizing passenger boarding speed.
However, the basic platform arrangement suffers from several well known problems, such as passengers falling under trains either deliberately or unintentionally and also litter from passengers falling onto the track. Although incidents of people falling under trains are not common, they result in significant disruption to the network and are traumatic incidents for everyone present. The problem of litter on the track has also increased in recent years and can represent a serious health and safety risk on underground or sub-surface systems where the litter will remain in tunnels until it is cleared up.
Platform screen door systems, or automated platform gates, are well known in the railway industry as one approach of dealing with these problems. Due to the problem of lining up doors on the platform and the train, these systems are usually only installed on lines where the rolling stock is standardized, which in practice is on metro or underground systems, although some dedicated high speed systems are also provided with screens, or screen doors.
As the doors are quite heavy, weighing in some cases over 100 kg, and hence require a significant energy to move the door, the door and gate systems are usually provided with an obstruction detection so that a brake can be applied in the event that someone or something becomes trapped between the leading door edge and the system in the closed and locked position. Presently installed systems use microprocessor based software control to control the motor speed in accordance with predetermined characteristic profiles, in which the final portion of the door movement is comparatively slow so that in the event that someone or something becomes trapped, lower forces are applied which will not cause serious injuries.
The known systems suffer from a problem in that it is possible for the doors under microprocessor/software control to go into overspeed by overshooting the characteristic profile. Due to the nature of the injuries which could be caused by failure of the software controlling the door, it has to be validated to a minimum level of SIL2.
The present disclosure relates to an apparatus and a method for controlling the closing of a door or gate in a platform screen door system that enhances the safety of the system.
The present disclosure relates to a control system for a platform screen door system. The platform screen door system has a door drive means and a microprocessor door drive control means adapted to control the opening and closing of the door according to a predetermined profile. The control system comprises at least one probe adapted to monitor the drive means and/or door motion. The control system further comprises a controller adapted to control the door drive means, wherein, in use, the controller brakes the door drive means if a signal from the probe is outside a predetermined door operating envelope.
In an embodiment, according to the present disclosure, the drive means comprises at least one motor driven pulley and the probe is adapted to measure the current drawn by the motor that drives the pulley.
The probe is adapted to measure the speed of the door and/or the current drawn by the door drive means.
Once the door has reached a predetermined speed, the microprocessor is adapted to maintain the door at a constant speed for a predetermined time or distance and then to brake the door to a second predetermined speed. The second predetermined speed is lower than the first predetermined speed and, if the controller determines that the door speed is higher than the second predetermined speed, the drive means are braked.
The probe is a Hall probe and the time between successive rising edges of the Hall probe signals is measured such that the door speed is within limit when the current drawn between successive rising edges does not exceed a predetermined limit.
A door operating envelope has selectable operating boundaries for different doors.
The control system, according to the present disclosure, includes an advantage over the known systems by providing both obstruction detection and door overspeed control using independent hardware control, in addition to software control. Thus, safety is enhanced through redundancy and diversity.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.